The invention pertains generally to railway car wheels and more particularly to a railway car wheel structure especially adapted to dissipate the heat generated by braking action applied to the periphery of the rim of the wheel.
Many railway cars are provided with brake blocks that are applied to the periphery of the rim of the wheels for the purpose of producing a braking action to reduce the running speed of the car and bring it eventually to a standstill or to prevent it from overspeeding when running downhill. During such brake applications heat is generated by the friction of the brake block rubbing against the surface of the rim so that the temperature of the wheel rises substantially with the maximum temperature developing in the rim of the wheel where the braking force is applied.
The wheel is therefore subjected to changing temperature gradients which create internal stresses. These stresses reach such magnitude that they cause fissures to develop that eventually result in wheel failure and possible derailment of the car.
The detrimental affect of the heat generated by the braking action in railway car wheels is recognized in U.S. Pat. No. 4,281,745 issued to Xaver Wirth on Aug. 4, 1981 in which FIG. 6 illustrates ribs secured to the brake discs for cooling the brake itself. However, none of the prior art suggests a practical cooling structure for cooling the rim of a railway car wheel that is braked by the application of brake blocks or shoes to the rim of the wheel and therefore has no brake discs on which ribs can be mounted.